The international patent application publication WO 98/39694 describes switch-mode power converters using an inductance coupled to the regulator output and at least a high side switch coupled between the input supply voltage and the inductance. The switch-mode regulator provides a transient response speed-up in the presence of large load transients. The speed-up is achieved by coupling a first bypass switch between the regulator output and the input voltage and a second bypass switch between the regulator output and the circuit common connection. During normal operation these bypass switches are off, but in the event of a large load transient substantially disturbing the regulator output, one of the bypass switches is momentarily turned on to couple the regulator output to the input voltage or circuit ground as appropriate to bring the regulator output within a narrow range around the nominal output voltage. Operation of the bypass switches is disabled on startup until the regulator output is within a predefined range, and whenever the regulator output exceeds a limit range indicative of a fault condition.
A drawback of such regulators is that due to large load transients the deviation of the actual output from the required output voltage is relatively large.